1. Technical Field
The invention relates to a device for the generation of mechanical energy comprising an internal combustion engine and an expansion engine which is fed with superheated steam from a steam generator, wherein the exhaust gases of the internal combustion engine are injected into the steam generator to use the waste heat thereof.
2. Prior Art
The DE 196 10 382 C2 describes a combined engine consisting of a combustion engine and an expansion engine in the form of a steam engine. The steam engine receives the high pressure steam from a steam generator. The high pressure steam is preheated by the cooler of the engine block of the combustion engine. The steam generator is exposed to the exhaust gases of the combustion engine, the combustion engine and the steam engine operate on a common crank shaft. In order to filter pollutants from the exhaust gases an oxidizing catalytic converter is arranged upstream of the steam generator in the exhaust pipe which is guided through the steam generator to the atmosphere. The DE 196 10 382 C2 suggests to insert fuel from time to time or continuously into the exhaust pipe upstream of the catalytic converter to increase the portion of the power of the steam engine. This additional fuel is burnt in the catalytic converter together with unburnt fuel from the combustion engine.
This is an after-burning of unburnt fuel from the combustion engine by an oxidizing catalytic converter in the usual way. The steam generator primarily uses the waste heat of the exhaust gases including the combustion heat generated in the oxidizing catalytic converter. Additionally fuel can be injected into the oxidizing catalytic converter only to increase the power of the steam generator still more.
The amount of fuel which can be additionally burnt in the oxidizing catalytic converter is limited by the constructive properties of the oxidizing catalytic converter. The oxidizing catalytic converter is designed to after-burn the remnants of unburnt fuel in the exhaust gases or certain pollutants, but not to serve as the heat source for a steam generator. The steam engine operating on the same crank shaft as the combustion engine essentially is to make use of the heat of the exhaust gases and thereby increase the efficiency.